NEXTMap® World 30™ has been an ambition of the Intermap® data engineers since the processing of the SRTM collection back in 2001. The lack of ground control for the SRTM dataset was an obvious area that could stand to be improved. Our radar engineers knew that when the right ground control became available a fantastic opportunity would present itself to update this detailed dataset and make it the best circum-world coverage dataset available. The secret ingredient was the introduction of NASA ICESat data. In raw form, this global set of LiDAR ground control points was a cumbersome mix of cloud strike points and anomalies. Intermap polished the raw ICESat data using an extensive filtering process that cleaned the data set and reduced it to 820 million ground control points, scattered with predictable regularity around the globe and boasting a vertical accuracy of 25cm RMSE or better. With this control data, an SRTM error mask could finally be created and applied to adjust the Z values of the SRTM DSM.
An Oblique View of Terrain Mapping